1. Field of the Invention
The invention relates generally to trailer frame structures; and, more particularly, to a light-weight structure having an improved tongue structure and improved structural frame members.
2. State of the Prior Art
Various structures for trailers that are to be towed behind vehicles are known. One such class of trailer structures that have special requirements is the class of trailers used to haul snowmobiles and other devices that are readily propelled in one direction, but are difficult to move in the opposite direction. Generally, these trailers are supported on two wheels, are preferably light in weight, and often have a wood deck and other wooden parts. Various forms of ramps and tilt beds are known and used for loading vehicles to be hauled. In prior art trailer structures the rear edge of the deck is often exposed to wear and damage from snowmobile skis sliding onto the deck. In other prior art trailer structures an auxiliary wear strip fastened over the rear edge. The wear strips often become damaged or detached from the deck due to repeated loading operations. These tendencies to wear and damage in the prior art trailer structures result in a requirements for considerable maintenance and generally diminishes the value and utility of such trailer structures.
Another aspect of prior art snowmobile trailer structures were those that allowed the deck to swivel laterally with respect to the tongue to thereby allow the snowmobile to be driven forward and off the trailer. These swivel or rotating structures were safety hazards in that they could malfunction while being towed. Such malfunction often resulted either in the trailer becoming uncontrollable or the hauled snowmobile becoming dislodged from the trailer. Neither situation is acceptable.
Most recreational trailers utilize a tongue structure that may be characterized as a box beam that is constructed of a closed cross-sectional shape. Most often the shape is square or rectangular. Flat, solid or channel shapes are generally not used because these shapes are unduly heavy when the necessary strength is provided, and the shapes are more easily bent or deformed than the box beam configuration.
The tongue is adapted to support a hitch at one end, where the hitch is designed for coupling with a mating hitch structure on a towing vehicle.
A common method of unloading snowmobiles, or other devices that need forward movement, is to turn the towing vehicle at a sharp angle to the trailer tongue, thereby allowing the snowmobile to drive down an auxiliary ramp at the front of the trailer and past the end of the towing vehicle. There is a major problem with this procedure. When the turn is too severe because the angle of the towing vehicle to the trailer tongue is too sharp, the side of the tongue may engage the support of the mating hitch on the towing vehicle. If the engagement is too severe, the tongue may become dented or bent, or the vehicle hitch may be damaged. If the force on the side of the tongue is severe enough, the torque on the fasteners that mount the hitch on the tongue may cause the fasteners to be weakened, bent, break, or pull away from the tongue. This type of damage and the damage that can occur if the trailer and vehicle jack-knife are common and are clearly undesirable.
Various prior art trailer frames have been constructed of steel, wood, and combinations of materials. Trailers such as used for transporting snowmobiles characteristically are used in inclement weather and are often used in snow an wet conditions. These conditions tend to cause rust and damage to steel parts and to cause rot in wooden frame parts. These damages require maintenance and reduce the longevity of such trailer structures.
Prior art metal frames utilized bent and formed structural members. This type of fabrication generates deformation of material at bend areas and tends to result in a weakened structure. This is especially a problem with light weight material such as aluminum.
It has been common in prior art tilt bed trailers to have longitudinal members mounted beneath the trailer bed and arranged parallel to the tongue to hold the tongue alignment. Such arrangements work for lateral stability, but do not provide any substantial vertical support between frame spans that support the trailer deck. Damage often results to such structures if the trailer deck is caused to return to the supported down position with too much force as can occur if the load Is applied too rapidly when the bed is tilted.
In many situations it is desirable to be able to utilize auxiliary sides and ends. While it is known to use removable sides having downwardly extending stakes that are removably retained in stake holders, or boots, the stake holders have usually been constructed of bent, sheared, and welded component parts. These types of prior art structures are expensive to manufacture, and often add unneeded weight to the frame.
The labor and expense to form these elements are great, and more uniform method of manufacture is desirable. It has not been known to form the trailer frame members from extruded light-weight material such as aluminum.